This instrument is very similar to the one shown Kratzer making
in his 1528
portrait by Holbein:

The times shown on the different surfaces do not agree: 9:30
on one face and 10:30 on the other two. It has also been observed
that the gnomon has not been set for a northerly latitude but
rather one corresponding to North Africa. These discrepancies
can be connected to other inconsistencies within the painting:
setting of the cylindrical
sundial, and the lute with a broken
string. These should be related to the theme of limitation
of human science which is limited by the finite nature of humanity.

The representation of the polyhedral form should also be seen
as a further manifestation of Holbein's mastery of the science
of perspective as demonstrated by other details like the representation
of the lute and tour
de force of perspective, the anamorphic skull.